. >> tonight heartbreaking good-byes in connecticut. investigators say they are looking at every bullet, anding every angle. >> the gun processing the evidence, analyzing the evidence. >> from the wreckage much ruined lives, trying to piece together understanding of how this happened. plus what, we've learned with friday's first victim. the shooter's own mother. she told me the guns, she would take them shooting because that was a way that a single mom could, you know, relate to her son. >> she was devoted and that was her job, to look after him. >> tonight the inside story from the family's friends and neighbors. i'm john scott in for shepard smith. we begin with the search for a motive. it is clear friday's shooting in newtown, connecticut can have no rational explanation. the act itself is the definition of insanity. still at this hour, investigators are work to unravel the sequence of events that ended with a man killing his own mother, driving to an elementary school and murdering 26 innocent children and adults before committing s